Noisy central heating since fitting underfloor heating

[chippymike]

Hi,
I fitted underfloor heating to my combi central heating system.
Since fitting it I have a loud noise like water whooshing through the rads. I have made several changes to try and cure the problem. It seems the most likely cause is air in the system.
I have drained the system several times and flushed the underfloor again with a hose, now i have noise in the manifold as well.
The boiler is in the loft its an 10 year old Baxi Max flow. The underfloor and the central heating have there own flows from the loft and are controlled with 2 2 port valves. both systems share the return.
The Noise starts as soon as the boiler fires and the 2 ports open on the central heating side.
I spoke to the tech guy at the underfloor supplier and he suggested fitting a low loss header but I spoke to a guy who makes low loss headers and he did not think that it was a solution.
I tried fitting AAVs on the flow before the 2 ports and one on the return at the top of the system but this did not help.
I have spoked to several heating engineers and the best they could come up with was try a can of leak sealer.
All advice gratefully received
cheers mike.

 

[SimonG]

What underfloor system did you use?

 

[Rickster123]

Some pics of the setup would really help..

 

[chippymike]

Pro warm with pex al pex barrier pipe

 

[chippymike]

what pics would help? I could give more details of the lay out if that helps

 

[ShaunCorbs]

Pro warm with pex al pex barrier pipe

next step i would do is pressure test (water) the system at 10 bar least it will tell you if you have a leak/ in the air is coming in via the pipework

 

[chippymike]

I tested the ufh to 6 bar when i fitted it but was thinking of doing it again. the boiler doesn't loose pressure but I guess that doesn't mean I don't have some kind of leak.

 

[ShaunCorbs]

I tested the ufh to 6 bar when i fitted it but was thinking of doing it again. the boiler doesn't loose pressure but I guess that doesn't mean I don't have some kind of leak.

do the whole system least you have piece of mind then (not boiler)

 

[kris]

A low loss header would help depending on size and layout of system / pumps

 

[chippymike]

the boiler is in the loft and I believe the pump in the boiler is on the return. the ufh is on the ground floor and the manifold has a pump on the flow side. the manifold id on the ground floor.